1. Field of the Invention
The present invention relates to an electric circuit apparatus of an injection molding machine which consists of a plurality of circuit elements connected to one another.
2. Description of the Related Art
In general, an injection molding machine includes a plurality of electrical circuit elements, such as various sensors, switches including relays, and circuit boards. Such circuit elements are connected to one another by use of connection wires (connection cables) to thereby constitute an electric circuit apparatus.
Conventionally, such an electric circuit apparatus is configured to include standard circuit elements at the time of shipment from a plant. However, in order to cope with demands of users, the electric circuit apparatus is configured to enable the user to change the standard circuit by means of connecting an additional circuit element later. Specifically, in the vicinity of each circuit element, a junction terminal (e.g., a junction terminal disclosed in Japanese Patent Application Laid-Open (kokai) No. 7(1995)-272781) is disposed. A circuit (line) of an additional circuit element is not connected directly to an existing circuit element, but is connected to the existing circuit element via the junction terminal. Therefore, when an additional circuit element is to be connected to an existing circuit element, a connection wire connected to the junction terminal is first removed, and then the additional circuit element is connected to the existing circuit element by use of the junction terminal.
However, such a conventional electric circuit apparatus has the following drawbacks.
First, since a plurality of junction terminals are disposed at dispersed locations corresponding to respective circuit elements, a large installation space is required. In addition, when an additional circuit element is to be connected, the location of a corresponding junction terminal must be confirmed with reference to an instruction manual, which is cumbersome. Further, depending on the location of the junction terminal, the connection work is difficult to perform, and misconnection is likely to occur.
Second, since connection wires are typically connected to the junction terminal by use of screws, the connection work requires much labor and a long time. In addition, when screw-fastening or connection work is not performed properly, connection wires may come off due to vibration or the like. Therefore, the conventional scheme is not satisfactory from the viewpoint of reliability.
An object of the present invention is to provide an electric circuit apparatus of an injection molding machine in which wiring lines, each divided into two line segments for connection of an additional circuit element, are provided in a centralized manner in order to reduce the overall installation space.
Another object of the present invention is to provide an electric circuit apparatus of an injection molding machine which facilitates connection work and shortens the time required for the connection work.
Still another object of the present invention is to provide an electric circuit apparatus of an injection molding machine which enhances certainty and reliability of additional connections which are formed on a user side.
In order to achieve the above-described objects, the present invention provides an electric circuit apparatus of an injection molding machine, the electric circuit apparatus consisting of a plurality of mutually connected circuit elements and including a connector board which comprises a plurality of connection terminals to which connection wires can be connected, and a plurality of wiring lines each divided into two line segments in order to enable an additional circuit element to be connected to an existing circuit element provided as a standard element. The line segments of each wiring line are electrically connected to a pair of connection terminals. A connection element for short-circuiting or an additional circuit element is selectively connected to the pair of connection terminals.